Scan based testing is also referred to as JTAG, which is the joint test action group that developed the standard IEEE standard 1149.1, which is hereby incorporated by reference. This testing involves a serial shift register methodology for performing tests and diagnostics of a digital system. Data, sent via JTAG test application, is pushed into the system's registers. The data is then shifted through the desired device to be tested, and the results are sent back to the JTAG application. For example, the test may be to merely determine whether a test pattern moves through the device without change. The results are compared against expected results, and any mismatch indicates a diagnostic failure.
In the prior art, scan testing is performed by a running a JTAG application on a computer that is connected to the unit under test (UUT). Thus, a user is limited to working with whatever graphical user interface or command prompt format the JTAG application uses to operate.
Working with different scan tools presented problems. For example, users would have to learn different command sets or have situations requiring the stopping and restarting of different tools to perform certain experiments.